2007 ISUZU KB P190 check engine

ENGINE DRIVEABILITY AND EMISSIONS 6E–89
Breaker Box Connection Type B
Breaker box connection type B, check for “short to
power supply circuit” and “power, signal voltage check”
between the engine control module (ECM) and
electrical components.
5 1
4 3 2
(1) Engine Control Module (ECM)
(2) Harness Adapter
(3) Breaker Box (4) Digital Voltage Meter
(5) ECM - Harness Adapter Connection

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ISUZU KB P190 2007

6E–90 ENGINE DRIVEABILITY AND EMISSIONS
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
Circuit Description
The on-board diagnostic system check is the starting
point for any driveability complaint diagnosis. Before
using this procedure, perform a careful visual/physical
check of the ECM and engine grounds for cleanliness
and tightness.
The on-board diagnostic system check is an organized
approach to identifying a problem created by an
electronic engine control system malfunction.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation or a wire broken inside
the insulation. Check for poor connections or a
damaged harness. Inspect the ECM harness and
connector for improper mating, broken locks, improperly
formed or damaged terminals, poor terminal-to-wire
connection, and damaged harness.
Te s t D e s c r i p t i o n
Number(s) below refer the step number(s) on the
Diagnostic Chart:
1. The Check Engine Lamp (MIL) should be ON steady
with the ignition “On”, engine “Off”. If not, “No Check
Engine Lamp (MIL)” chart should be used to isolate the
malfunction.
2. Checks the Class 2 data circuit and ensures that the
ECM is able to transmit serial data.
3. This test ensures that the ECM is capable of
controlling the Check Engine Lamp (MIL) and the Check
Engine Lamp (MIL) driver circuit is not shorted to
ground circuit.
4. If the engine will not start, “Engine Cranks But Will
Not Run” chart should be used to diagnose the fault.
6. The Tech2 parameters which is not within the typical
range may help to isolate the area which is causing the
problem.
12. This vehicle is equipped with ECM which utilizes an
electrically erasable programmable read only memory
(EEPROM).

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ENGINE DRIVEABILITY AND EMISSIONS 6E–91
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
StepAction Value(s) Yes No
1 1. Ignition “On”, engine “Off”. 2. Check the “CHECK ENGINE” lamp (MIL).
Does the “CHECK ENGINE” lamp turn “On”? — Go to Step 2Go to
No
CHECK
ENGINE Lamp
2 1. Using the Tech 2, ignition “On” and engine “Off”. 2 . A t t e m p t t o d i s p l a y “ E n g i n e D a t a ” w i t h t h e T e c h 2 .
Does the Tech 2 display “Engine Data” and “O
2Sensor Data”? — Go to Step 3Go to Step 7
3 1. Using the Tech 2, ignition “On” and engine “Off”. 2. Select the “Miscellaneous Test” and perform the“Malfunction Indicator Lamp” in “Lamps”.
3. Operate the Tech 2 in accordance with the Tech 2 instructions.
Does the “CHECK ENGINE” lamp turn “Off”? — Go to Step 4Go to
CHECK
ENGINE LAMP On Steady
4 Attempt to start the engine. Does the engine start and continue to “Run”? —Go to Step 5Go to
Engine
Cranks But Will Not Run
5 1. Using the Tech 2, ignition “On” and engine “Off”. 2. Select the “Read DTC Infor By Priority” in“Diagnostic Trouble Code”.
3. Are any DTCs stored? —Go to
DTC
Chart Go to Step 6
6 Compare typical scan data values displayed on the Tech 2 “Engine Data” and “O
2 Sensor Data”.
Are the displayed values within the range? —Refer to
SYMPTOM
DIAGNOSIS Refer to
TYPICAL
SCAN DATA
7 Using the DVM and check the data link connector power supply circuit.
1. Ignition “Off”, engine “Off”.
2. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 8
8 Using the DVM and check the data link connector ground circuit.
1. Ignition “Off”, engine “Off”.
2. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 9
V
16
B58
5
4B58

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ISUZU KB P190 2007

6E–92 ENGINE DRIVEABILITY AND EMISSIONS
9 Using the DVM and check the data link connectorground circuit.
1. Ignition “On”, engine “Off”.
2. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 10Repair faulty
harness and verify repair
10 Using the DVM and check the data link connector communication circuit.
1. Ignition “On”, engine “Off”.
2. Check the circuit for short to power supply circuit.
Was the DVM indicated battery voltage?
—Repair faulty
harness and verify repair Go to Step 11
11 Using the DVM and check the data link connector communication circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 12
12 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 13
Step
Action Value(s) Yes No
VV
5
4B58
V
B-582
C-56(J2)
ΩΩ
B-58230

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ISUZU KB P190 2007

6E–94 ENGINE DRIVEABILITY AND EMISSIONS
NO CHECK ENGINE LAMP (MIL)
Circuit Description
The check engine lamp should be illuminated and
steady for about five seconds with the ignition “ON” and
the engine stopped. Ignition feed voltage is supplied to
the check engine lamp bulb through the meter fuse.
The Engine Control Module (ECM) turns the check
engine lamp “ON” by grounding the check engine lamp
driver circuit.
Diagnostic Aids
An intermittent check engine lamp may be cased by a
poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check for the
following items:
• Inspect the ECM harness and connections for improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire connection,
and damaged harness.
• If the engine runs OK, check for a faulty light bulb, an open in the check engine lamp driver circuit, or an
open in the instrument cluster ignition feed.
• If the engine cranks but will not run, check for an open ECM ignition or battery feed, or a poor ECM to
engine ground.
No Check Engine Lamp (MIL)
Step Action Value(s) Yes No
1 Check the “Meter” fuse (15A). If the fuse is burnt out, repair as necessary.
Was the problem found? — Verify repair Go to Step 2

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–95
2 Using the DVM and check the “CHECK ENGINE”lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Ignition “On”.
4. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 5Go to Step 3
3 Check the “CHECK ENGINE” lamp bulb. If the bulb is burnt out, repair as necessary.
Was the problem found? — Verify repair Go to Step 4
4 Using the DVM and check the “CHECK ENGINE” lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the meter connector and ECM connector.
3. Check the circuit for open circuit.
Was the problem found?
— Verify repair Go to Step 5
5 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 6
6 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify repair —
Step
Action Value(s) Yes No
V
32C56(J2)
3217C56(J2)B24

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ISUZU KB P190 2007

6E–96 ENGINE DRIVEABILITY AND EMISSIONS
CHECK ENGINE LAMP (MIL) “ON” STEADY
Circuit description
The check engine lamp should always be illuminated
and steady for about five seconds with ignition “ON” and
the engine stopped. Ignition feed voltage is supplied
directly to the check engine lamp indicator. The Engine
Control Module (ECM) turns the check engine lamp
“ON” by grounding the check engine lamp driver circuit.
The check engine lamp should not remain “ON” with the
engine running and no DTC(s) set. A steady check
engine lamp with the engine running and no DTC(s)
suggests a short to ground in the check engine lamp
driver circuit.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:
• Poor connection or damaged harness - Inspect the ECM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness.
Check Engine Lamp (MIL) “ON” Steady
Step Action Value(s) Yes No
1 1. Ignition “Off”, engine “Off”. 2. Disconnect the ECM connector.
3. Ignition “On”.
Was the “CHECK ENGINE” lamp turned on? — Go to Step 2Go to Step 4

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–97
2 Using the DVM and check the “CHECK ENGINE”lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the meter connector and ECM connector.
3. Check the circuit for short to ground circuit.
Was the problem found?
— Verify repair Go to Step 3
3 Replace the meter assembly. Is the action complete? — Verify repair —
4 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 5
5 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify repair —
Step
Action Value(s) Yes No
32C56(J2)

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ISUZU KB P190 2007